The invention relates to a clamping apparatus for clamping an object to a member having an opening therein. The invention has a particular use in clamping accessories, such as a canopy, to a box portion of a pick-up truck.
Pick-up trucks are known to have a box portion for carrying objects such as tools, farm equipment, sand, gravel, hay, etc. The box portion typically has an end portion adjacent the cab of the truck and has two parallel side portions extending towards the rear of the truck. Each of the parallel side portions is typically comprised of thin gauge sheet metal bent to form an inverted U-sectioned rim having a flat upper portion and two closely spaced apart vertical wall portions. Usually, the flat portion has rectangular apertures therein for receiving wooden stakes to increase the height of the side portions as is particularly useful when hauling hay.
Since the advent of the incorporation of rectangular apertures in the truck box side portions, various pick-up truck accessories such as camper tops, canopies, tool boxes, etc. have become available. These accessories are often designed to include mounting holes which align with the rectangular openings in the side portions. Thus, various devices have been designed to cooperate with the rectangular openings to secure accessories to the box of the truck.
U.S. Pat. No. 4,531,774 to Whatley discloses such a device. The device has wedge shaped arms which are hingedly connected to a base member. A bolt is inserted through an aperture in the base member and has an abutment plate secured to its head. The abutment plate abuts both of the wedge shaped arms and tends to spread the arms apart as the bolt is tightened. The wedge shaped arms have outer contact surfaces which are intended to abut closely spaced apart vertical wall portions extending vertically downwards from the rectangular opening in the side portions of the truck box. For the device to work properly, the side portions of the truck must have these vertical wall portions and the vertical wall portions must be rigid enough to resist deformation due to direct sideways forces applied by the contact surfaces of the arms of the device. Not all trucks have vertical wall portions that are sufficiently deep, to cooperate with the arms and which are sufficiently rigid to resist deformation.
U.S Pat. No. 4,607,991 to Porter discloses another clamping device for a truck having closely spaced vertical wall portions. This device has a base member with hinged arms having latching studs affixed to distal ends thereof. The latching studs are intended to be received in holes previously made in the vertical wall portions. The use of this device may present problems in that the holes in the vertical wall portions must be accurately positioned to align with the latching studs. Typically, space is limited in the vicinity of a rectangular opening, rendering the task of making accurately aligned holes difficult.
U.S. Pat. No. 3,623,690 to Bargman discloses another device which relies on the use of vertical wall portions. The device includes two wedge members which are moved relative to each other by turning a bolt. The wedge members move outwards away from each other and abut against the vertical wall portions. Again, with this device the vertical wall portions must be sufficiently rigid to resist deformation.
Accessories for pick-up trucks are becoming increasingly popular and many have a considerable mass and corresponding weight. When such devices are fastened to a truck using the devices disclosed in the patents above, the closely spaced apart vertical wall portions of the truck are placed under considerable load.
Based on the above patents, it appears there is a need for a clamping device which may be used to secure accessories to a pick-up truck without imposing excessive sideways forces on sidewalls of the truck. In addition, there appears to be a need for a clamping device which may be used to secure accessories to a pick-up truck without the need for rigid closely spaced vertical wall portions adjacent the rectangular openings in the side portions of the truck.